Starting structure of large-section earth pressure balance push bench in water-rich sand layer

Abstract

A starting structure of a large-section earth pressure balance pipe jacking machine on a water-rich sand layer comprises a tunnel portal, a structural side wall and an enclosure structure, the tunnel portal is arranged on the structural side wall, the enclosure structure is arranged on the back side of the structural side wall, the starting structure further comprises a short steel cylinder, an end reinforcing body and a steel sheet pile curtain, the short steel cylinder is arranged on the tunnel portal and the enclosure structure in a penetrating mode, and the end reinforcing body is arranged on the end reinforcing body. A sealing structure is arranged on the inner wall of the short steel cylinder, the end reinforcing body is arranged on the back side of the enclosure structure, and the steel sheet pile curtain is arranged on the back side of the end reinforcing body. The steel sheet pile curtain is arranged on the back side of the end reinforcement body according to the characteristics that the water permeability of the stratum of the water-rich sand layer and the flowability of the sand layer are high, the water permeability of the stratum and the flowability of sand water are reduced through the combination of the steel sheet pile curtain and the end reinforcement body, and meanwhile the short steel cylinder is arranged and the sealing brush is used for improving the sealing and water stopping performance of the tunnel portal. The water and sand gushing risk of the tunnel portal can be effectively reduced, the water stopping effect is good, the safety risk is low, and the safety risk problem of starting of the large-section earth pressure balance push bench in the water-rich sand layer can be effectively controlled.

Description

Technical Field

[0001] The utility model relates to the technical field of pipe jacking method tunnel construction, in particular to a launching structure of a large-section earth pressure balance pipe jacking machine in a water-rich sand layer. Background Technique

[0002] The pipe jacking method is a trenchless construction method, which has the advantages of fast construction speed, high construction efficiency and little construction impact. It is widely used in the construction of tunnels or underground passages crossing various obstacles such as railways, roads, rivers or buildings, such as subway station entrances, underground pedestrian passages, underground vehicle passages, underground utility tunnels, etc.

[0003] In order to ensure the safety during pipe jacking launching, reinforcement construction is usually carried out in the launching section. When a large-section pipe jacking machine launches under a water-rich sand layer, due to the strong water permeability of the formation and the fluidity of the sand layer, the conventional reinforcement methods may not have good effects. Moreover, due to the large space of the shell of the large-section pipe jacking machine, it is difficult to ensure the sealing effect of the portal, which is easy to cause water leakage and sand gushing phenomena. In severe cases, it may lead to ground settlement or collapse, greatly affecting the construction safety. Content of the Utility Model

[0004] In order to solve the above technical problems, the utility model provides a launching structure of a pipe jacking machine in a water-rich sand layer with good water stop effect and low safety risk, which can effectively control the safety risk problem of a large-section earth pressure balance pipe jacking machine launching in a water-rich sand layer.

[0005] In order to achieve the above purpose, the technical solution adopted by the utility model is: a launching structure of a large-section earth pressure balance pipe jacking machine in a water-rich sand layer, including a portal, a structural side wall and a retaining structure. The portal is arranged on the structural side wall, the retaining structure is arranged on the back side of the structural side wall, and also includes a short steel cylinder, a head reinforcement and a steel sheet pile curtain. The short steel cylinder penetrates through the portal and the retaining structure, a sealing structure is arranged on the inner wall of the short steel cylinder, the head reinforcement is arranged on the back side of the retaining structure, and the steel sheet pile curtain is arranged on the back side of the head reinforcement.

[0006] As a further improvement of the utility model, the sealing structure includes at least two sealing brushes arranged on the inner wall of the short steel cylinder, a cavity is formed between two adjacent sealing brushes, and sealing grease is injected into the cavity.

[0007] As a further improvement of the utility model, the head reinforcement is formed by grouting and reinforcing the soil with double-tube rotary jet grouting piles.

[0008] As a further improvement of the utility model, the steel sheet pile curtain is composed of a plurality of steel sheet piles, and the plurality of steel sheet piles are arranged along the outer contour line of the head reinforcement.

[0009] As a further improvement of the utility model, it further includes a portal sealing curtain cloth, and the portal sealing curtain cloth is arranged on the portal.

[0010] As a further improvement of the utility model, the portal sealing curtain cloth includes a circular ring fixing plate and a rubber curtain cloth plate. The circular ring fixing plate fixes the rubber curtain cloth plate on the portal, and the rubber curtain cloth plate is arranged along the circumference of the portal.

[0011] The beneficial effects of the utility model are as follows: In the utility model, aiming at the characteristics of strong water permeability and sand layer fluidity in the water-rich sand layer stratum, a steel sheet pile curtain is arranged on the back side of the end reinforcement body. The steel sheet pile curtain and the end reinforcement body are combined to reduce the water permeability of the stratum and the fluidity of sand and water. At the same time, a short steel cylinder is arranged and a sealing structure is adopted to improve the water sealing performance of the portal seal, which can effectively reduce the risk of water and sand gushing at the portal, has the characteristics of good water sealing effect and low safety risk, and can effectively control the safety risk problem of the large-section earth pressure balance pipe jacking machine starting in the water-rich sand layer. Description of the Drawings

[0012] Figure 1 It is a schematic diagram of the overall starting structure;

[0013] Figure 2 It is a schematic diagram of the layout of the end reinforcement body and the steel sheet pile curtain;

[0014] Marking description: Portal 1, Structural side wall 2, Retaining structure 3, Short steel cylinder 4, Sealing brush 41, End reinforcement body 5, Steel sheet pile curtain 6, Portal sealing curtain cloth 7, Circular ring fixing plate 71, Rubber curtain cloth plate 72, Pipe jacking machine 8. Detailed Implementation Modes

[0015] The following further describes the utility model in conjunction with specific embodiments and the drawings.

[0016] As Figure 1 、 2 shown, a starting structure of a large-section earth pressure balance pipe jacking machine 8 in a water-rich sand layer includes a portal 1, a structural side wall 2, a retaining structure 3, a short steel cylinder 4, an end reinforcement body 5, a steel sheet pile curtain 6 and a portal sealing curtain cloth 7.

[0017] The portal 1 is reserved on the structural side wall 2 during the construction of the working shaft, and the retaining structure 3 is arranged on the back side of the structural side wall 2.

[0018] The short steel cylinder 4 is a cylinder structure made of steel plates and sections, which is penetrated through the portal 1 and the retaining structure 3 and arranged in a circle along the circumference of the opening of the portal 1. Two sealing brushes 41 are welded inside the short steel cylinder 4. Each sealing brush 41 is arranged in a circle along the inner wall of the short steel cylinder 4. A cavity is formed between the two sealing brushes 41, and sealing grease is injected into the cavity to isolate sand and water in front of the starting cutterhead. Through the short steel cylinder 4 and the two sealing brushes 41 inside the short steel cylinder 4, the sealing and water-stopping performance of the portal 1 is improved, and the risk of water and sand gushing can be effectively avoided. In other embodiments, the number of the sealing brushes 41 can also be set to more than two.

[0019] The end reinforcement 5 is arranged on the back side of the retaining structure 3. The end reinforcement 5 is formed by grouting and reinforcing the soil with double-tube jet grouting piles. The longitudinal reinforcement length of the end reinforcement 5 is 0.4 - 1 m, the transverse reinforcement length extends 2 - 3 m outside the pipe jacking contour line, and the bottom of the jet grouting pile is at least 2 m lower than the bottom surface of the channel.

[0020] The steel sheet pile curtain 6 is arranged on the back side of the end reinforcement 5. The steel sheet pile curtain 6 is composed of multiple steel sheet piles, and the multiple steel sheet piles are arranged in a U-shaped structure along the outer contour line of the end reinforcement 5. By combining the steel sheet pile curtain 6 with the end reinforcement 5, the permeability of the formation and the flow of sand and water are reduced, and the role of isolating sand and water is played during the end reinforcement and the initial excavation of the pipe jacking.

[0021] The portal sealing curtain 7 is arranged on the portal 1. The portal sealing curtain 7 includes a circular ring fixing plate 71 and a rubber curtain plate 72. The circular ring fixing plate 71 fixes the rubber curtain plate 72 on the portal 1. The rubber curtain plate 72 is arranged in a circle along the portal 1 and faces the pipe jacking machine 8, playing a role in sealing and water stopping.

[0022] During the construction of the above structure, the steel sheet pile curtain 6 is constructed first, and after the construction of the steel sheet pile curtain 6 is completed, the end reinforcement 5 is constructed. After the construction of the steel sheet pile curtain 6 and the end reinforcement 5 is completed, the pipe jacking machine 8 is lowered into the well for assembly and debugging, and then the portal sealing curtain 7 is installed on the portal 1. Then, the retaining structure 3 within the range of the portal 1 is demolished section by section, and the short steel cylinder 4 is installed inside the portal 1. After the inspection and confirmation of the end reinforcement effect and the preparatory work, the pipe jacking machine 8 starts. After the pipe jacking machine 8 starts and the shell enters the portal 1, the portal sealing curtain 7 and the sealing brushes 41 inside the short steel cylinder 4 wrap the shell of the pipe jacking machine tightly. Before the pipe jacking machine 8 reaches the steel sheet pile curtain 6, the steel sheet piles of the steel sheet pile curtain 6 need to be pulled out. After the last steel sheet pile is pulled out, through the two sealing settings of the sealing brushes 41 and the portal sealing curtain 7, and the set initial excavation parameters of the pipe jacking machine 8, the smooth start of the large-section pipe jacking machine 8 in the water-rich sand layer is realized.

[0023] In summary, the present utility model has been made into an actual sample as described in the specification and illustrations and has been tested through multiple uses. From the results of the use tests, it can be proven that the present utility model can achieve its intended purpose, and its practical value is beyond doubt. The above-described embodiments are only used to conveniently illustrate the present utility model and do not impose any formal restrictions on the present utility model. Any person with ordinary knowledge in the relevant technical field, without departing from the technical features of the present utility model, using the technical content disclosed by the present utility model to make partial modifications or equivalent embodiments of decorations, and without departing from the technical feature content of the present utility model, still fall within the scope of the technical features of the present utility model.

Claims

1. Starting structure of a large-section earth pressure balance pipe jacking machine in water-rich sand layer, comprising a portal, a structural side wall and a retaining structure, wherein the portal is arranged on the structural side wall, and the retaining structure is arranged on the back side of the structural side wall, characterized in that: It also includes a short steel cylinder, an end reinforcement body and a steel sheet pile curtain. The short steel cylinder is penetrated through the portal and the retaining structure. A sealing structure is provided on the inner wall of the short steel cylinder. The end reinforcement body is arranged on the back side of the retaining structure. The steel sheet pile curtain is arranged on the back side of the end reinforcement body.

2. The starting structure of a large-section earth pressure balance pipe jacking machine in a water-rich sand layer according to claim 1, characterized in that: The sealing structure includes at least two sealing brushes provided on the inner wall of the short steel cylinder. A cavity is formed between two adjacent sealing brushes, and sealing grease is injected into the cavity.

3. The starting structure of a large cross-section earth pressure balance pipe jacking machine in a water-rich sand layer according to claim 1, characterized in that: The end reinforcement body is formed by grouting and reinforcing the soil body with double-tube rotary jet grouting piles.

4. The starting structure of a large-section earth pressure balance pipe jacking machine in a water-rich sand layer according to claim 1, characterized in that: The steel sheet pile curtain is composed of a plurality of steel sheet piles, and the plurality of steel sheet piles are arranged along the outer contour line of the end reinforcement body.

5. The starting structure of a large cross-section earth pressure balance pipe jacking machine in a water-rich sand layer according to claim 1, characterized in that: It also includes a portal sealing curtain. The portal sealing curtain is arranged on the portal.

6. The starting structure of a large-section earth pressure balance pipe jacking machine in a water-rich sand layer according to claim 5, characterized in that: The portal sealing curtain includes a circular ring fixing plate and a rubber curtain plate. The circular ring fixing plate fixes the rubber curtain plate on the portal, and the rubber curtain plate is arranged along the circumference of the portal.

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